/* ContentHandler.java -- Abstract class for handling content from URL's Copyright (C) 1998, 1999 2000, 2001 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ package java.net; import java.io.IOException; /** * Written using on-line Java Platform 1.2 API Specification, as well * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998). * Status: Believed complete and correct. */ /** * This is an abstract class that is the superclass for classes that read * objects from URL's. Calling the getContent() method in the * URL class or the URLConnection class will cause * an instance of a subclass of ContentHandler to be created for * the MIME type of the object being downloaded from the URL. Thus, this * class is seldom needed by applications/applets directly, but only * indirectly through methods in other classes. * * @author Aaron M. Renn (arenn@urbanophile.com) * @author Warren Levy */ public abstract class ContentHandler { /*************************************************************************/ /* * Constructors */ /** * Default, no-argument constructor. */ public ContentHandler() { } /*************************************************************************/ /** * This method reads from the InputStream of the passed in URL * connection and uses the data downloaded to create an Object * represening the content. For example, if the URL is pointing to a GIF * file, this method might return an Image object. This method * must be implemented by subclasses. * * @param urlc A URLConnection object to read data from. * * @return An object representing the data read * * @exception IOException If an error occurs */ public abstract Object getContent(URLConnection urlc) throws IOException; /*************************************************************************/ /** * This method reads from the InputStream of the passed in URL * connection and uses the data downloaded to create an Object * represening the content. For example, if the URL is pointing to a GIF * file, this method might return an Image object. This method * must be implemented by subclasses. If the object doesnt match any type in * classes it returns null. * * @param urlc A URLConnection object to read data from. * * @return An object representing the data read * * @exception IOException If an error occurs * * @since 1.3 */ public Object getContent(URLConnection urlc, Class[] classes) throws IOException { Object obj = getContent (urlc); for (int i = 0; i < classes.length; i++) { if (classes [i].isInstance (obj)) return obj; } return null; } } // class ContentHandler